The present invention relates to wireless communications systems, and more particularly to a monitoring and command system for transceivers that carry telephony signals between wireless telephones and a broadband distribution network.
The prior art teaches the use of existing cable television network cables to carry telephony signals between a telephone network and remote transceiver sites in defined cells or sectors. The remote transceivers are used to establish wireless telephony communication links with wireless telephones that are operating within an area covered by each remote transceiver. To increase the number of wireless telephone subscribers that can use the wireless telephone system it has been suggested to decrease the size and operational range of each cell or sector, and to increase the number of cells or sectors required to provide wireless telephone service to a given area. Having cells or sectors of decreased size permits greater reuse of the limited number of frequency channels allocated for wireless telephone service because other cells or sectors located at a closer range can reuse the same frequency channels for additional calls without signal interference. The advantages of reducing cell or sector size to increase the call carrying capacity of the wireless telephone network is offset by the requirement for additional remote transceivers for the additional cells. This offset is minimized by utilizing an existing broadband distribution network to provide the communications path between remote transceivers in each of the cells or sectors and a central transceiver. The central transceiver acts as the interface with the remote transceivers, via the broadband distribution network, and a base transceiver station acts as the interface between the telephone network and the central transceivers.
To carry wireless telephony signals over a broadband distribution network, as described above, a predetermined bandwidth on the network is typically allocated for this purpose. However, as required, more bandwidth may be allocated to carry wireless telephony signals. To most efficiently use a given bandwidth to carry wireless telephony signals between wireless telephones and the telephone network, a combination of frequency and time division multiplexing, and other forms of signal multiplexing, is utilized. This requires base transceiver station equipment that acts as the interface with the telephone network and the wireless telephone system. With the base transceiver station equipment is a central transceiver (RASP), also called a Headend Interface Converter (HIC), that interfaces with the broadband distribution network, and it must function with telephony signals in the wide frequency spectrum of radio frequency signals on the telephone network, and up to 1000 Mhz over the broadband distribution network. This system also requires a plurality of remote transceivers, also called cable microcell integrators (CMI) or Remote Antenna Drivers (RADs), in each of the cells or sectors that can carry many channels of telephony signals between the wireless telephones and the central transceiver via the broadband distribution network, without creating signal interference with the telephony signals in adjacent cells or sectors. In addition, the remote transceivers (RADs) must function with and translate telephony signals in the wide frequency spectrums of up to 1000 Mhz on the broadband distribution network and between 1850-1990 MHz for the radio link between remote transceivers and wireless telephones. To function together properly in such a system wireless telephone system there is a need for efficient operational communication between the central transceiver and remote transceivers.
Thus, there is a need in the art for means to monitor and control the operations of the central transceiver and remote transceivers. In this respect, a recurring problem of the prior art is the creation of a flexible and reliable means for encoding data and commands to be received from and transmitted to the remote transceivers, for receiving information from the remote transceivers, for monitoring the operation of the transceivers, and for sending commands to the remote transceivers to control their operation. It is necessary for the encoding means to convey data and commands in as flexible and compact a form as possible to preserve communications bandwidth and thereby to allow a large number of remote transceivers to be monitored and controlled from each base station, and it is preferable that the encoding allow a flexible a network configuration as possible.
The present invention is directed to a monitoring and command system for use in a wireless communications system including at least one central transceiver and a plurality of remote transceivers used for transmitting and receiving telephony signals to and from wireless telephones.
According to the present invention, each of the remote transceivers (RADs) are connected to a broadband distribution network that carries telephony signals between the remote transceivers (RADs) and the central transceiver (RASP). The central transceiver includes at least one remote antenna signal processor (RASP) connected to the broadband distribution network and a control unit connected to the at least one remote antenna signal processor, and the monitoring and command system controls operations of the remote antenna signal processor and the remote transceivers.
The monitoring and command system includes the control unit, which exchanges messages with each of the remote antenna signal processors for controlling operations of the remote antenna signal processors, including monitoring the operation of the antenna signal processors and the central and remote transceivers, and controlling signal levels and frequencies of the telephony signals. Each exchange of messages between the control unit and a remote antenna signal processor comprises a completed exchange of messages between the control unit and the remote antenna signal processor before initiation of an exchange of messages between the control unit and a next remote antenna signal processor.
The monitoring and command system further includes the at least one antenna signal processor, which exchanges messages with the remote transceivers for controlling operations of each of the remote transceivers, including monitoring operations of each of the remote transceivers, relaying messages between the control unit and each one of the remote transceivers, and controlling the signal levels and frequencies of the telephony signals. The messages of an exchange of messages between the at least one remote antenna signal processor and a selected one of the remote transceivers are interspersed with the messages of an exchange of messages between the at least one remote antenna signal processor and at least one other of the remote transceivers.
The messages exchanged among the control unit, the remote signal signal processors and the central and remote transceivers includes a message number field containing a value identifying the meaning of the message, a message tag field containing a value identifying a given message in a sequence of messages, wherein the message tag field is used in an exchange of messages between a remote antenna signal processor and a remote transceiver, and a plurality of data fields containing message information wherein the contents of each data field are defined by the contents of the message number field. The data fields contain information including an identification of a remote transceiver intended as a recipient of a message, information determining the operating parameters of the remote transceivers, and information pertaining to the status and operation of the remote transceivers.